From James Mirtle of the Globe & Mail:
The lottery system is pretty complicated, but the basics are that teams can only move up a maximum of four spots and down a maximum of one spot. Only one team "wins" the lottery – everyone else moves based on the team that won
That leaves every team with a maximum of only three different spots they can pick in. (The Toronto Maple Leafs, for example, can end up with the first, fifth or sixth overall pick.)
The Leafs have a 8.1% chance of picking first overall, a 74.7% chance of drafting 5th, and 17.2% chance of this year getting even worse. Here's a fancy shmancy flow chart from @majupra that may help you visualize all of the different possibilities.
You can even try your hand at the draft lottery simulator over at the Edmonton Oilers site.
Where will the Leafs end up drafting?
| 6 - Only real Leaf fans will pick this | 58 |
| 5 - This is the spot Devereaux kept us from | 106 |
| 1 - History books will mark tonight as the day things changed for the better | 66 |